Periodontium Flashcards
ILO 8.5b: have knowledge in the form and function of teeth, and the oral environment, in health and disease
what are the roles of the periodontium?
4
tissue that supports and surrounds teeth
retains tooth in socket
resists masticatory loads
defensive barrier against threats from oral environment
what is the junctional epithelium?
physical barrier separating the body tissues from the oral environment
what are periodontal diseases divided into?
2
diseases of the gingiva
diseases of all periodontal tissues
what are the properties of cementum?
4
covers root dentine
very similar structure to bone
provides attachment for some periodontal fibres
laid down by cementocytes
what is the difference between acellular and cellular cementum?
5, 7
acellular
* no cells
* usually adjacent to dentine
* formed first - primary cementum
* cervical 2/3 of root
* Sharpey’s fibres from PDL
cellular
* contains cementocytes
* formed later - secondary cementum
* apical 1/3 of root and furnication regions
* no Sharpey’s fibres
* fibres parallel to surface
* no role in tooth attachment
* may represent a transitional form
what are the alternate classification names for acellular and cellular cementum?
2
acellular - acellular extrinsic fibre cementum
cellular - cellular intrinsic fibre cementum
describe the structure of alveolar bone
4
similar to bone elsewhere in body
‘cortical’ plate forms inner lining of tooth socket
penetrated by nutrient canals
inner ‘cancellous’ bone contains bone marrow
what is the function of alveolar bone?
2
provides attachment for periodontal ligament fibres - Sharpey’s fibres
supports the teeth
what happens to alveolar bone when teeth are lost?
1
alveolar process is reabsorbed, leaving a ‘residual ridge’
what does the periodontal ligament contain?
5
cells
extracellular matrix
fibres
nerves
blood vessels
what does the periodontal ligament matrix contain?
3
hylauronate GAGs
glycoproteins - fibroconectin
proteoglycans
what cells are present in the periodontal ligament?
5
fibroblasts
cementoblasts
osteoclasts and cementoclasts
epithelial cells
defence cells
cell rests of Malassez = epithelial cell cluster reminants of Hertwigs epithelial root sheath (HERS)
what kinds of nerves are present in the periodontal ligament?
2 (2,1)
sensory
* mechanoreceptors
* nociceptors
autonomic (sympathetic)
where does the blood supply to the periodontal ligament come from?
2
passes in to PDL? gingiva supply?
inferior and superior arteries passing into PDL
lingual and palatine arteries supply gingiva
what are the two types of periodontal ligament fibre and what do they do?
2
true periodontal ligament - attach tooth to bone at or apical to alveolar crest
gingival ligament - fibres above the alveolar crest